<template>
  <canvas id="canvas" :width="props.width" :height="props.height" @click="handleCanvas"> </canvas>
</template>

<script setup>
const props = defineProps({
  width: {
    type: Number,
    default: 100,
  },
  height: {
    type: Number,
    default: 30,
  },
  quantity: {
    type: Number,
    default: 4,
  },
  line: {
    type: Number,
    default: 10,
  },
  spot: {
    type: Number,
    default: 50,
  },
});

let trueCode = ref(""); //保存正确的验证码
// 只用于传参，并且数组长度不能「多于」下面验证码遍历的次数，不然最终得到的 trueCode 会有问题
let verificationCode = [];

function draw(showCode) {
  var canvas_width = document.querySelector("#canvas").clientWidth;
  var canvas_height = document.querySelector("#canvas").clientHeight;
  var canvas = document.getElementById("canvas"); // 获取到canvas
  var context = canvas.getContext("2d"); // 获取到canvas画图
  canvas.width = canvas_width;
  canvas.height = canvas_height;
  var sCode = "a,b,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,W,X,Y,Z,1,2,3,4,5,6,7,8,9,0";
  var aCode = sCode.split(",");
  var aLength = aCode.length; // 获取到数组的长度

  // 验证码个数
  for (var i = 0; i < props.quantity; i++) {
    var j = Math.floor(Math.random() * aLength); // 获取到随机的索引值
    var deg = (Math.random() * 30 * Math.PI) / 180; // 产生0~30之间的随机弧度
    var txt = aCode[j]; // 得到随机的一个内容
    showCode[i] = txt.toLowerCase(); // 依次把取得的内容放到数组里面
    var x = 10 + i * 20; // 文字在canvas上的x坐标
    var y = 20 + Math.random() * 8; // 文字在canvas上的y坐标
    context.font = "bold 23px 微软雅黑";

    context.translate(x, y);
    context.rotate(deg);

    context.fillStyle = randomColor();
    context.fillText(txt, 0, 0);

    context.rotate(-deg);
    context.translate(-x, -y);
  }

  // 验证码上显示的线条
  for (var i = 0; i < props.line; i++) {
    context.strokeStyle = randomColor();
    context.beginPath();
    context.moveTo(Math.random() * canvas_width, Math.random() * canvas_height);
    context.lineTo(Math.random() * canvas_width, Math.random() * canvas_height);
    context.stroke();
  }
  // 验证码上显示的小点
  for (var i = 0; i < props.spot; i++) {
    context.strokeStyle = randomColor();
    context.beginPath();
    var x = Math.random() * canvas_width;
    var y = Math.random() * canvas_height;
    context.moveTo(x, y);
    context.lineTo(x + 1, y + 1);
    context.stroke();
  }
  // 最后把取得的验证码数组存起来，方式不唯一
  var num = showCode.join("");
  trueCode.value = num;
}
// 得到随机的颜色值
function randomColor() {
  var r = Math.floor(Math.random() * 256);
  var g = Math.floor(Math.random() * 256);
  var b = Math.floor(Math.random() * 256);
  return "rgb(" + r + "," + g + "," + b + ")";
}
const emits = defineEmits(["getCode"]);
// canvas 点击刷新
function handleCanvas() {
  draw(verificationCode);
  emits("getCode", trueCode.value);
}

onMounted(() => {
  draw(verificationCode);
  emits("getCode", trueCode.value);
});
</script>

<style lang="scss" scoped>
#canvas {
  margin-right: 1%;
  display: block;
  border: 1px solid #ccc;
  border-radius: 5px;
  cursor: pointer;
  margin-right: 80px;
}

.input-val {
  width: 50%;
  background: #ffffff;
  height: 2.8rem;
  border-radius: 5px;
  border: none;
  padding: 0 0 0 12px;
  border: 1px solid rgba(0, 0, 0, 0.2);
}
</style>
